Argentina’s “Fiscal Innocence II” law is now in effect, aiming to address undeclared funds – often referred to as “mattress dollars.” However, full implementation is hampered by a lack of supporting regulations. Despite the law’s passage, no provinces within Argentina have formally joined the scheme, raising concerns about potential tax claims. This lack of provincial adhesion creates uncertainty regarding the law's overall success and equitable application across the country. The absence of clear rules leaves room for varying interpretations and possible conflicts between the national government and individual provinces. Experts suggest that without broader provincial support, the initiative may fall short of its intended goals of bringing undeclared wealth into the formal economy and boosting government revenue. This situation highlights ongoing fiscal federalism challenges within Argentina.